Dasberg, S., Dept. of Soil Physics, The Volcani Center, Bet Dagan, Israel
Bar-Akiva, A., Dept. of Citriculture, Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel
Spazisky, S., Dept. of Citriculture, Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel
Cohen, A., Dept. of Citriculture, Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel

A long-term experiment was carried out in a mature orange grove comparing broadcasting versus continuous application of nitrogen at three rates (80, 160, 280 kg ha-1), 22 kg P ha-1 and 126 kg K ha-1 annually. The trees were irrigated with minispriklers wetting 70% of the soil area. The level of NO3-N in the leaves varied according to the rate of N application. Leaf K and P content were not affected by fertilization. High N applications caused excess N in the soil solution. The rate of N application did not affect orange yield, fruit size or quality. Fertigation at 160 kg N ha-1 caused higher yields than when the same amount of fertilizer was broadcast. At the high application rate, no differences between modes of application were found. © 1988 Kluwer Academic Publishers.